外源H_2S缓解黄瓜种子萌发过程中干旱胁迫伤害的生理机制

Physiological Mechanism of Exogenous H_2S in Alleviating Drought Stress-Induced Injury in Germination of Cucumber Seed

以黄瓜品种‘新津研四号’为材料,1mmol·L^(-1) NaHS为H_2S供体,采用质量分数为10%聚乙二醇(PEG-6000)模拟干旱胁迫,研究外源H_2S缓解黄瓜种子萌发过程中干旱胁迫伤害的机制。结果表明,H_2S可以显著提高干旱胁迫下黄瓜种子的发芽势、发芽率、胚轴长、根长和鲜质量;显著增加脯氨酸和可溶性糖的质量分数,提高种子淀粉酶和酯酶活性,还能诱导增强超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)的活性,并降低丙二醛(MDA)的质量摩尔浓度和质膜透性。即外源H_2S可以通过调节渗透调节物质的质量分数,增强水解酶和抗氧化保护酶的活性来有效缓解干旱胁迫对萌发黄瓜种子造成的伤害,促进种子的萌发生长。

The seeds of cucumber(Cucumis sativus L.)variety‘Xinjinyan 4’were treated with 1.0 mmol·L-1 NaHS(H 2S donor)for exploring physiological mechanisms of H 2S on seed germination under drought stress,which simulated by 10%polyethylene glycol 6000(PEG-6000).The results showed that,under PEG stress,exogenous H 2S significantly increased seed germination energy,germination rate,root and hypocotyl length and fresh mass,it also increased mass fractions of proline and soluble sugar,activated amylase and esterase activity.Meanwhile,the results also indicated that H 2S apparently regulated the activities of SOD,CAT and POD,and resulted in the significant decrease of MDA molality and membrane permeability.These results suggested that H 2S could alleviate drought-induced damage during seed germination and consequently induced cucumber seed germination through increasing the mass fractions of osmotic regulation substances and improving the activities of hydrolase and antioxidant enzymes.